Catheters for the introduction or removal of fluids may be located in various venous locations and cavities throughout the body for introducing or removing fluids. Such catheterization may be performed by using a single catheter having multiple lumens. A typical example of a multiple lumen catheter is a dual lumen catheter in which one lumen introduces fluids and one lumen removes fluids. Catheterization may also be performed by using separate, single lumen catheters inserted through two different incisions into an area to be catheterized. Such multiple catheter assemblies are known as TESIO® catheters sold by Medical Components, Inc. of Harleysville, Pa.
Generally, to insert any catheter in a blood vessel, the vessel is identified by aspiration using an introducer device, such as a syringe having a long hollow needle in accordance with the Seldinger technique. Typically, a needle is attached to a syringe and inserted under the patient's skin, with the plunger being withdrawn as the needle is inserted. When blood enters the syringe attached to the needle, indicating that the vessel has been found, the syringe body is removed and a thin guide wire is introduced through the needle lumen and into the interior of the vessel. The needle is then removed, leaving a portion of the guide wire within the vessel and the remainder projecting outwardly to a point beyond the surface of the patient's skin. Other guide wire introducing devices and syringes are also available. At this point, the catheter is inserted by the physician over the guide wire using one of several known techniques.
In the case of single-lumen catheters typically used in multiple catheter assemblies (e.g., a Tesio® catheter), a physician may use an introducer sheath. If a Tesio® catheter is used for hemodialysis, for example, each catheter may be inserted in two separate veins. Alternatively, each catheter may be inserted in two different locations of the same vein, such as the internal jugular vein or in a single insertion site as described in U.S. Pat. No. 5,624,413. The introducer sheath is simply a large, stiff, thin-walled tube which serves as a temporary conduit for the permanent catheter which is being placed. The introducer sheath is positioned by placing a dilator device inside of the introducer and passing both the dilator and the introducer together into the vessel over the guide wire. The guide wire, which is partially within the vessel after insertion as described above, and the dilator are then removed, leaving the thin-walled introducer sheath in place. The catheter is then placed through the introducer sheath.
In each case, the first step is aspirating the vessel or area to be catheterized prior to introducing the guide wire. This is often troublesome, especially when aspirating blood vessels, due to the flashback of blood. Arterial blood may spurt from the needle insertion point with considerable force and may contact a physician or other attendant assisting the physician, causing the risk of contamination with blood borne pathogens, such as HIV virus or hepatitis. A second problem, which is of greater concern to the patient, is exposing certain venous blood vessels or other body cavities to atmospheric pressure. Veins are often under negative pressure as blood is being drawn back to the thoracic cavity due to the process of inspiration during the breathing cycle, and a hole in a venous blood vessel could lead to air being drawn into the blood vessel, creating an air embolism.
In other types of catheterization procedures, such as a pleural effusion where fluid which collects around the lungs is drained, it is important to have a closed system guide wire introduction device which prevents atmospheric air from entering the thoracic cavity. Breathing movement creates negative pressure in the thoracic cavity, which, in combination with the air in the lungs, keeps the lungs expanded. The introduction of air into the thoracic cavity could cause the lungs to partially collapse. It is therefore important during the insertion of a guide wire for catheterization that the risk of introducing air into the thoracic cavity or a vessel be minimized.
One attempt to solve these problems is disclosed in U.S. Pat. No. 5,613,663, which discloses a valve device within a two-piece housing that requires the valve to be assembled within the device prior to assembly of the two pieces that comprise the housing. However, the valve disclosed in this patent requires arterial blood pressure to close the valve. It would be beneficial to provide a valve that is housed in a one-piece housing to facilitate manufacturing of the device, and that includes a valve closure mechanism that does not require arterial blood pressure to close the valve.